Mr Engledow, A Case of Repulsion in Wheat. 433 
__ A Case of Repulsion in Wheat. By F. L. ENGLEDow, B.A., 
St John’s College. (Communicated by Professor Biffen.) 
| [Read 9 March 1914.] 
| The plants which supplied the evidence of repulsion comprised 
! the second generation (F,) of the cross 
i 
| Smooth Black x Essex Rough Chaff 
and the two characters concerned were: 
j (1) Roughness of Chaff, 
| (2) Black Colour of Chaff. 
The term chaff, as used here, refers to the glumes only of the ear. 
It is, however, practically certain that an examination of the outer 
paleae would justify the inclusion of these parts with the glumes 
/as far as the experimental characters are concerned. 
_ The following details concerning the parents suffice for the 
purposes of this paper. 
“Smooth Black” is a variety of wheat obtained by Professor 
Biffen as one constituent of the second generation of the cross 
| Rivet x Fife. 
Its genetic constitution has not yet been determined but, as two 
years of growing have shown, it breeds true. 
The glumes are glabrous and of a deep and burnished black 
colour, the black pigment occurring in the sub-epidermal tissues. 
Types which possess glumes of this nature will be referred to 
as “Smooth Black.” 
“Essex Rough Chaff” is, agriculturally, a very familiar variety. 
‘In common with most other types of wheat it has glumes entirely 
devoid of the black colour which characterises the other parent. 
There is a further distinction between its glumes and those of 
Smooth Black, viz. the presence of numerous hairs. This com- 
bination of characters in the glume is designated by the term 
“Rough White.” 
In all, the second generation which resulted from the crossing 
of these two varieties contained 213 plants. Sorting by eye— 
which was fully confirmed by an examination with the dissecting 
microscope—furnished the following classification : 
Rough Black Rough White Smooth Black Smooth White 
120 45 AT 3 
VOL. XVII. PT. V. 29 
